Abstract: A seal for a rotating system with two sealing units which are arranged one behind the other along a main axis H, the sealing units each having a through-hole for a shaft and being in interlocking engagement with each other in the circumferential direction and at least one axial compression spring element being arranged between the sealing units.

Abstract: A packing ring for a sealing device, having at least two segments that are arranged around a common main axis (X). In order to be able to detect the current condition of wear, the packing ring has at least one indicator means that indicates a position of at least one of the segments in a radial direction (R) perpendicular to the main axis (X) of the packing ring.

Abstract: Piston ring arrangement (40) with a piston ring (50) encircling a main axis (X), the piston ring (50) having a sealing surface (58) directed radially outward and a contact surface (55) directed radially outward, the sealing surface (58) being radially outside of the contact surface (55). To improve the service life of piston rings for reciprocating compressors, the piston ring arrangement (40) has a retaining ring (70) encircling the main axis (X) with a retaining surface (72) directed radially inward, the piston ring (50) and the retaining ring (70) being situated such that the retaining surface (72) and the contact surface (55) are adjacent in the radial direction.